| abstract |
Provided is a lubricant composition which has achieved a good balance between fuel consumption saving and extreme-pressure properties, while having shear stability, oxidation stability and wear resistance. Specifically, provided is a lubricant composition which is characterized by containing a base oil, a viscosity index improver, a molybdenum-based friction modifier, a boron-containing dispersant, and a sulfur/phosphorus-based extreme-pressure additive or at least two extreme-pressure additives selected from among a sulfur-based extreme-pressure additive, a phosphorus-based extreme-pressure additive and a sulfur/phosphorus-based extreme-pressure additive, and which is also characterized in that: the base oil is composed only of a synthetic oil; the base oil has a kinematic viscosity of from 3 mm 2 /s to 10 mm 2 /s (inclusive) at 100°C; the viscosity index improver is a resin having a number average molecular weight (Mn) of from 1,000 to 10,000 (inclusive); the mass ratio of the boron atoms (B) contained in the boron-containing dispersant to the molybdenum atoms (Mo) contained in the molybdenum-based friction modifier, namely (B)/(Mo) is from 1 to 5 (inclusive); and the mass ratio of the sulfur atoms (S) contained in the extreme-pressure additive(s) to the phosphorus atoms (P) contained in the extreme-pressure additive(s), namely (S)/(P) is from 10 to 20 (inclusive). |